48 percent of adults in the U.S. have inadequate health literacy

Health problems that place limitations on daily activities and result in pain that interferes with normal work activities were more common among older individuals with poor health literacy, according to a study in the current issue of Archives of Internal Medicine.

The Institute of Medicine reports that 48 percent of adults in the U.S. have inadequate health literacy, defined as the ability to obtain, process and understand basic information and services needed to make appropriate decisions regarding health, according to background information in the article. Besides basic reading skills, individuals need to be able to read and understand numerical information such as that on prescription bottles and be able to read and interpret document information such as appointment slips.

Michael S. Wolf, Ph.D., M.P.H. of the Feinberg School of Medicine, Northwestern University, Chicago, and colleagues used data from a survey of 2,923 Medicare enrollees in Cleveland, Houston, Tampa, and Fort Lauderdale-Miami, Fla. In a one-hour in-person interview, individuals' physical and mental health status were assessed. Questions included medical history, alcohol and tobacco use and height and weight. Standardized mental and physical health test scores were determined. The average age of participants was 71 years.

Approximately one third of those surveyed had marginal (11 percent) or inadequate (22.2 percent) health literacy. Individuals with lower health literacy were more likely to have never smoked and to abstain from alcohol than individuals with adequate health literacy, the researchers report. Individuals with inadequate health literacy had significantly higher rates of certain chronic conditions, including high blood pressure, diabetes mellitus, heart failure and arthritis. Individuals with inadequate health literacy were more likely to report activity limitations related to health, including activities of daily living and pain that "quite a bit" or "extremely" interfered with normal work activities. "The magnitude of these associations were large and clinically important," the authors write.

Previous studies have suggested that inadequate health literacy is linked to worse knowledge of proper health behaviors and lower adherence to medical instructions; that despite access to health care the quality of medical encounters may be compromised when health care providers do not communicate at a level that is understood; and that patient education materials may be too complex or written at too high a level to be helpful. "Over time, these factors could contribute to the worse health status seen among the older patients with low health literacy in this study," the authors suggest.

"Although the causal pathways between low health literacy and disease-specific health outcomes remain unclear, this study provides further evidence of the likelihood that inadequate health literacy detrimentally affects health," the authors conclude. "To develop appropriate and responsive interventions, future studies should discern how adults with lower health literacy recognize health issues, and they should identify barriers to seeking out appropriate health care services. In addition, interventions are needed that can help physicians and other health care professionals recognize and address the special needs of patients with limited health literacy."